SU148043A1 - The method of obtaining nitriles of aliphatic acids - Google Patents

Description

Nitriles are used as raw materials for the production of primary and secondary amines, used as solvents for plastics, and also as extrapirating agents for flotation.

The known periodic methods for the preparation of nitriles consist in the effect of an excess of gaseous ammonia on aliphatic acids at elevated temperatures and pressures up to 5-7 atm in the presence of a catalyst (salts of fatty acids or dehydrating agents: phosphoric acid, silica gel, etc. -) There are also continuous processes, carried out at atmospheric pressure.

The disadvantage of the described methods is the relatively low yield of the finished product (90%) and the highly complex technological design of the process of regeneration of excess ammonia.

The proposed method of nitriding at 15 atm using the GIPH-101 dehydrating catalyst (State Chemical Committee, Spec. No. EU-32-53) makes it possible to conduct a continuous process with a yield from 95 to 99% for acids with different molecular weights or their mixtures and to simplify and cheapen the technological scheme of ammonia regeneration.

When nitrile fatty acids, “for example, stearic, both components (liquid ammonia and stearic acid), under a pressure of 15 atm and a temperature of 390 ° served in a reaction furnace of a flow type of stainless steel.

For each liter of catalyst GIPH-101, 0.3 l of stearic acid and 0.12 kg of liquid ammonia fall during the hour. The ammonia on the way to the reactor is evaporated and the stearic acid is heated. The components must not be mixed in order to avoid the formation of the ammonium salt of stearic acid, capable of plugging the reazhtor.

Acid is fed through a separate pipe to the upper zone of the reactor. The mixture from the reactor through the cooler enters the separator, where ammonia gas is separated from the liquid product.

Ammonia gas enters the refrigerator, condenses and collects in a container.

The mixture of liquid products from the separator and the tank is throttled and fed into a continuously operating distillation column, in which ammonia at 9-11 atm is distilled off and in liquid form enters the synthesis column again. The VAT residue consists of two layers: the lower aqueous and the Upper - stearlonitrile with a small admixture of stearylamide and unreacted acid.

After distillation of the water and distillation under vacuum (ml of mercury), an almost colorless product is obtained with a melting point of 36-37 ° and a boiling point of 180-194 °.

By nitrile various fat fractions from C to C20, products are obtained with the following characteristics:

Subject invention

The method of producing nitriles of aliphatic acids by the action of gaseous ammonia on aliphatic acids at a temperature of 390 °, characterized in that the process is carried out using a catalyst of the type GIPH-101 (TU No. EU-32-53, State Chemical Committee) at a pressure of 15 atm.